The application of azonia-cyanine dyes for nucleic acids imaging in mitochondria

Five cyanine dyes (1a-e) with azonia unit have been prepared by the reaction of pyrido[1,2−a]pyrimidinium ions and suitable aldehydes. Before further research, their photo and thermal stabilities were determined in the first place. At least 88% absorption remained after 5 h irradiating illustrated all of these dyes had excellent photo stability. Meanwhile, the decomposition temperature of dyes was around 200 °C which demonstrated they had good thermal stability. Therefore, the good photo and thermal stability made them possible to be probes. Subsequently, the optical properties of probes toward nucleic acids had been measured. TheirOFF–ON fluorescent responses (1a-d) towards nucleic acids were investigated. In addition, confocal microscopy imaging of probe 1a in live HeLa cells indicated that probe 1a could image mitochondrial nucleic acid.